Background: The problem of overweight and obesity in children and adolescents is considered an epidemic in both developed and developing world by the WHO. There has been little study on the relationship between health literacy and body weight among adolescents.This epidemiological study aims to investigate the association between low health literacy and overweight and obesity among a population of Chinese adolescents aged 12–16 years in the city of Nanning, China in 2012. Methods: This study was a population-based cross-sectional health survey utilising a two-stage random cluster sampling design. The sample consisted of high school students aged between 12–16 years with the total student population attending high schools in a large city as the sample frame. Health literacy was measured by the Chinese version of the short form of the Test of Functional Health Literacy translated for and validated among Taiwanese adolescents. Overweight and obesity were assessed in accordance to the recommendation of the World Health Organization (WHO) Global Database of Body Mass Index classification methods. Data were analysed using logistic regression modelling techniques with adjustment to the cluster sampling effect. Results: A total of 1035 students responded to the survey providing usable information with 628 (48.1%) respondents classified as high, 558 (42.8%) moderate, and 119 (9.1%) low levels of health literacy. After adjusting for potential confounding factors and the cluster sampling effect, low health literacy was significantly associated with overweight and obesity (OR = 1.84, 95% C.I. = 1.13-2.99). Conclusion: Results suggested that low health literacy level was associated with many aspects of adolescence health including their body weight. These results have public health implications on an important global problem of adolescence body weight. Enhancing the health literacy should be considered as part of the strategies in combating adolescence weight problem.